It is important in postage meters that the meter be physically secure from intrusion. As is well known, postage meters can be recharged; that is, additional value can be added to them in a variety of ways. For example, the postage meter can be physically taken down to a Post Office where the Post Office personnel will physically add incremental amounts of value to the meter or remove funds from the meter. Often times, the meter will have a external lock of a mechanical variety that is opened by a key. In addition, postage meters of this type have a combination associated therewith to allow for additional funds to be added to the meter. The combination adds additional security to the postage meter and prevents unauthorized personnel gaining access thereto.
It is important in this kind of system that the security be enhanced and thereby have a combination associated therewith in which only the authorized user can gain access. There are several existing methods for securing these kinds of meters from unauthorized personnel. These methods are generally effective but it is important to continue to develop new and better ways for securing the meters.
Often times, the Post Office will want to have the ability to change the combination generated by a microprocessor or the like to prevent unauthorized access to the postage meter. This capability is important in as much as personnel within the Post Office ma change thereby in certain circumstance, making it desirable to change the new combination necessary to unlock the postage meter. The ability to change the combination is important also because, since as is well known, postage meters are often leased to customers, the customers should not have the ability to open the meter at any time even if they somehow gained access thereto.
It is well known that schemes are used in a hotel to periodically change the locks. For example, if a customer uses the key to a hotel room and then inadvertently or purposely takes the key upon checking out of the hotel, there are schemes which will allow the hotel manager to give the next customer a new key thereby changing the lock or combination of the lock and allowing the new owner or the new customer access to the room. At the same time, the old key taken by the previous customer will no longer open the door. As before mentioned, this scheme is used to prevent unauthorized personnel from gaining access thereto. For hotel lock systems, there should be a set of combinations generated for implementation of the above-mentioned scheme. This can be accomplished in a variety of ways.
Similarly, in a postage meter, a desirable system should be provided that can perform a function very similar to that performed in the above-mentioned hotel system; that is, providing a set of combinations that will in a sequential manner provide access to the postage meter after using a physical key.
Thus, it is important in a manual recharging type postage meter to have means for generating a set of combinations in a simple and efficient manner to allow for enhanced security. At the same time, these combinations should desirably be generated in a random-like fashion so that it will not be easy to recreate the combination and thereby enter the locked postage meter.
A postage meter which uses series of combinations to unlock the meter for funding is disclosed in U.S. Pat. No. 4,097,923 in the names of Alton B. Eckert, Jr., Howell A. Jones, Jr. and Frank T. Check, Jr., assigned to the assignee of this patent application. In Eckert et al, there is disclosed a remote postage meter charging system using an advanced microcomputerized postage meter. This system is built around a microcomputer set and the meter contains seed numbers for generating postage funding combinations. The remote postage meter charging system has the capability of adding variable amounts of postage into the postage meter.
Another type of postage meter that will need a combination of numbers generated for it is a microcomputerized postage meter that does not have remote postage charging; that is, a postage meter that has a microcomputer within it that it also is physically under a mechanical lock and key. In addition to the mechanical lock, a series of numbers must be entered into the postage meter must be entered to open the postage meter to allow funding. This type of postage meter as before mentioned has to either be taken physically down to the Post Office or personnel must visit the customer's premises to allow the additional funding to take place.
Thus, it is important that in this kind of meter that an individual who has the key to the mechanical lock also has the combination to add the funding to the meter. In manually recharged kinds of meters that are physically carried to the Post Office or where authorized Post Office personnel comes to customer's business, again a combination is internally generated to unlock the meter.
Also, in postage meters of this type, the meter's combination should be secure to prevent unauthorized entry into the postage meter. Heretofore, there have been methods and apparatuses for generating a series of combination of numbers within the postage meter. Prior systems have provided adequate security and have operated satisfactorily. However, often times, the apparatus utilized in postage meters, such as those used in remote recharging postage meters to generate the combinations, are complex and expensive. In addition, these schemes often times require the use of valuable memory space in the postage meter. Thus, what is desired is a way of internally generating series of combinations in a microcomputerized postage meter that will allow for a random or pseudo random pattern and also reduce the amount of valuable memory space used in the microprocessor that heretofore has been necessary.